Contact blade assembly



Aug. :20, 1946 w. P. HERMAN 2,406,144 CONTACT BLADE ASSEMBLY I V FiledJune 14, 1941 INVENTOR ATTORNEY Patented Aug. 20, 1946 CONTACT BLADEASSEMBLY William P. Herman, Providence, R. I. Application June 14, 1941,Serial No. 398,098

2 Claims.

My present invention relates to the manufacture of electrical contactplugs and has particular reference to a novel construction of contactblades and novel methods of assembly of the contact blade with theelectric cord.

This application is a continuation in part of my copending applicationSer. No. 188,262, filed February 2, 1938, and entitled Contact plugassembly, issued July 8, 1941, Patent No. 2,248,082.

It is the principal object of my invention to provide a contact bladewhich'is firmly attached to the cord lead wire against pulls andabnormal strains.

It is an additional object of my invention to provide a contact bladewhich can be so attached to the end of a cord lead wire as to provide astrain relief which will withstand much more than the minimum requiredby the Underwriters Laboratories.

Another object of my invention is to provide various methods which willfacilitate the securing of cord lead wire to the contact blade, whichare easy and economical to practice, and which will facilitate assemblyof the final plug.

With the above and other advantageous features in View, my inventionconsists of a novel arrangement of parts, and novel methods ofmanufacture and assembly, more fully disclosed in the detaileddescription following, in conjunction with the accompanyin drawing, andmore specifically defined in the claims appended hereto.

In the drawing,

Fig. l is a perspective view of a self-anchoring contact blade embodyingmy invention;

Fig. 2 is an edge view thereof with the cord lead wire inserted thereinpreparatory to solder- Fig. 3 is a similar View, the cord lead wirebeing passed through the second slot after soldering;

Fig. 4 is a perspective view of the blade and cord soldered and readyfor assembly;

Fig. 5 is a plan view thereof.

In the manufacture of electrical contact plugs, it has been founddesirable to eliminate the use of screws, clamps, or other outsideanchoring means. It is therefore necessary to provide a blade and cordlead connection which affords a positive electrical contact ofsufiicient strength to meet the requirements of the UnderwritersLaboratories. While the present invention may be applied to any type ofblade, for the purposes of illustration I have shown the invention asapplied to a self-anchoring blade having intermediate shoulders forinterlocking with a plug slot.

Referring more in detail to the drawing illustrating my invention, andparticularly Fig. 1 thereof, the contact blade illustrated is preferablystamped in one, flat, integral piece. The blade comprises theconventional contact portion 32, the intermediate self-anchoringportion, and the upper cord receiving portion.

The upper cord receiving portion of the blade 32 is provided with atransverse slot 33 adjacent to its upper end, and a second transverseslot 34 below the slot 33 and extending from the opposite edge of theblade 32. The slot 34 preferably extends inwardly from the blad edge ata slight upward angle so that tension or pull on the cord lead wire willtend to slide the wire into the slot rather than outwardly.

The blade 32 may be soldered or spot welded to the lead wire. The baredend 35, of a cord 35, is attached to the upper edge of the blade 32,either by soldering or welding, as shown in Fig. 2. The wire is thenpassed through the slot 33, back through the slot 34, see Fig. 3, andthen reentrantly bent into the position shown in Figs. 4 and 5 ready forassembly.

This construction provides a strong relief against stresses and strains.Any strain on the cord is taken up by the convolutions of the insulatedportion of the conductor through the slots of the blade and very littleof the strain is transmitted to the bared contact portion.

While I have described a specific constructional embodiment of myinvention, and a Specific method of assembly, size and shape of theparts, in their relative arrangement, and in the method of assembly, maybe made to suit the requirements for difierent plug designs, withoutdeparting from the spirit and the scope of the invention as defined inthe appended claims.

I claim:

1. In combination, a contact blade for an electrical contact plugcomprising a flat, one-piece, rigid stamping of generally elongated formand having two spaced transverse slots extending inwardly from oppositeside edges adjacent the upper portion of said blade, the lower slotextending inwardly at an upward angle, and an insulated cord lead wirehaving its bared end fixed to one side of said blade adjacent the upperslot and extending upwardly above the upper slot, said insulated wirepassing alternately through the upper and then the lower slots and beingbent to extend upwardly in alignment with said blade.

2. In combination, a contact blade for an electrical contact plugcomprising a flat, one-piece,

it is obvious that changes in the wire having its bared end fixed to oneside of said 5 rigid stamping of generally elongated form and wardlyabove the upper slot, said insulated wire having two spaced transversslots extending inpassing alternately through the upper and then wardlyfrom the side and adjacent the upper the lower slots and being bent toextend upwardly portion of said blade, and an insulated cord lead inalignment with said blade.

blade adjacent the upper slot and extending up- WILLIAM P. HERMAN.

